Mice homozygous for targeted deletion of indoleamine 2,3 dioxygenase (IDO) produce no product from the IDO gene. These mice may be useful in studies of pregnancy and reproductive immunology (tryptophan degradation, T cell activation, clonal expansion) as well as autoimmune disease, tissue transplantation, fostering, acquired tolerance/T cell anergy, and immunosuppressive pathways.
Holly Koblish, Incyte Corporation
Homozygous mice are viable and fertile with normal immune system development and function. They exhibit no spontaneous autoimmune disorders. No gene product (mRNA or protein) from the indoleamine 2,3 dioxygenase (IDO) gene is detected in the epididymis. At embryonic day 10.5, endogenous protein is absent from all cells at the maternal-fetal interface when both parents are homozygous for the targeted gene. Allogeneic and syngeneic pregnancy outcomes are unaffected by this mutation. In contrast to wild-type, anti-proliferative treatments (CTLA4-Ig, IFNalpha, or CpG-ODN) do not suppress T cell expansion both in vivo and in vitro. In addition, homozygous dendritic cells isolated from lymph nodes draining (induced) tumor sites have no suppressor activity. These mice may be useful in studies of pregnancy and reproductive immunology (tryptophan degradation, T cell activation, clonal expansion) as well as autoimmune disease, tissue transplantation, fostering, acquired tolerance/T cell anergy, and immunosuppressive pathways.
A targeting vector was designed by the laboratory of Dr. Andrew Mellor (Medical College of Georgia) to replace exons 3-5 of IDO (encodes critical portions of the enzyme catalytic site) with the beta-galactosidase and neomycin resistance genes. Additionally, a translational "stop" codon (TAG) was introduced into exon 2. The construct was electroporated into 129/SvJ-derived embryonic stem (ES) cells and correctly targeted clones were injected into blastocysts. Male chimeric mice were mated with C57BL/6 females to produce heterozygotes, offspring were mated to produce homozygotes. These mice were sent to The Jackson Laboratory as Stock No. 005867. These mice were purchased by the laboratory of Dr. Holly Koblish (Incyte Corporation) where they were subsequently backcrossed to BALB/cAnNCrl for 5 generations (using a speed congenic protocol; see SNP note below). These mice were sent to The Jackson Laboratory (as Stock No. 012427). Upon arrival, mice were bred to BALB/cByJ (Stock No. 001026) for at least one generation to establish the colony.
A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. At least 1 marker, on Chromosome 4, is segregating.
|Allele Name||targeted mutation 1, Andrew L Mellor|
|Allele Type||Targeted (Null/Knockout)|
|Allele Synonym(s)||IDO-; Ido1-; Ido1-KO|
|Gene Symbol and Name||Ido1, indoleamine 2,3-dioxygenase 1|
|Strain of Origin||129X1/SvJ|
|Molecular Note||A Betagal and neomycin cassette replaced exons 3-5, which encode critical portions of the enzyme catalytic site. Also, a translation stop codon was introduced into exon 2. RT-PCR of total epididymis RNA from mutants showed no transcript was present. Western blot of mutant epididymis confirmed a lack of protein.|
|Mutations Made By|| |
Brendan Marshall, Medical College of Georgia
When maintaining a live colony, these mice are bred as heterozygotes or homozygotes.
When using the C.129X1(B6)-Ido1tm1Alm/J mouse strain in a publication, please cite the originating article(s) and include JAX stock #012427 in your Materials and Methods section.